Sensitivity and specificity of candidate criteria: AS versus NSBP
| Cohort | A | B | ||||||
|---|---|---|---|---|---|---|---|---|
| Sens | Spec (NSBP+HC) | LR+ | LR− | Sens | Spec | LR+ | LR− | |
| Global assessment | 1.00 | 0.95 (0.94) | 19.50 | <0.01 | 0.98 | 0.83 | 5.68 | 0.01 |
| ASAS definition | 0.83 | 0.76 (0.74) | 3.39 | 0.23 | 0.71 | 0.74 | 2.69 | 0.39 |
| MORPHO definition | 0.98 | 0.72 (0.71) | 3.54 | 0.03 | 0.88 | 0.72 | 3.16 | 0.16 |
| ER ≥2 | 0.98 | 0.97 (0.97) | 30.42 | 0.03 | 0.77 | 0.90 | 7.93 | 0.24 |
| BMO ≥2 | 0.83 | 0.76 (0.74) | 3.48 | 0.23 | 0.73 | 0.73 | 2.70 | 0.36 |
| BMO ≥2 and/or ER ≥1 | 0.98 | 0.72 (0.71) | 3.54 | 0.03 | 0.88 | 0.70 | 2.92 | 0.16 |
| BMO ≥2 and/or ER ≥2 | 0.98 | 0.73 (0.72) | 3.62 | 0.03 | 0.87 | 0.71 | 3.04 | 0.18 |
| BMO ≥3 | 0.80 | 0.89 (0.88) | 6.93 | 0.23 | 0.64 | 0.84 | 4.02 | 0.43 |
| BMO ≥3 and/or ER ≥1 | 0.98 | 0.85 (0.84) | 6.34 | 0.03 | 0.85 | 0.79 | 4.07 | 0.17 |
| BMO ≥3 and/or ER ≥2 | 0.98 | 0.85 (0.85) | 6.61 | 0.03 | 0.84 | 0.82 | 4.70 | 0.18 |
| BMO ≥4 | 0.80 | 0.92 (0.92) | 10.40 | 0.22 | 0.63 | 0.87 | 4.88 | 0.43 |
| BMO ≥4 and/or ER ≥1 | 0.98 | 0.88 (0.88) | 8.01 | 0.03 | 0.84 | 0.80 | 4.17 | 0.18 |
| BMO ≥4 and/or ER ≥2 | 0.98 | 0.89 (0.89) | 8.95 | 0.03 | 0.83 | 0.83 | 5.06 | 0.19 |
Sensitivity, specificity and likelihood ratios are expressed as mean values over four readers. The gold standard for calculating sensitivity and specificity was rheumatologist expert opinion.
AS, ankylosing spondylitis; ASAS, Assessment in SpondyloArthritis international Society definition: ≥2 SIJ quadrants with BMO on the same MRI slice or BMO in the same SIJ quadrant on ≥2 consecutive MRI slices; BMO, bone marrow oedema; ER, erosion; HC, healthy control; LR+, positive likelihood ratio; LR−, negative likelihood ratio; MORPHO, ≥2 SIJ quadrants with BMO on the same MRI slice or BMO in the same SIJ quadrant on ≥2 consecutive MRI slices or ≥2 SIJ quadrants with erosion on the same MRI slice or erosion in the same SIJ quadrant on ≥2 consecutive MRI slices or ≥1 SIJ quadrant with BMO plus ≥1 SIJ quadrant with erosion4; MRI, magnetic resonance imaging; NSBP, non-specific back pain; Sens, sensitivity; Spec, specificity; SIJ, sacroiliac joint.